Subjective well-being (SWB) can be defined as the degree to which people have positive thoughts and feelings about their lives and are often measured through self-reports of life satisfaction. One currently popular measure of SWB is the Satisfaction with Life Scale (Pavot and Diener 1993), which asks individuals the extent of their agreement or disagreement on a seven-point scale with five statements regarding life satisfaction as shown below.
Using the 1-7 scale below, indicate your agreement with each item by placing the appropriate number on the line preceding that item. Please be open and honest in your responding.                7-Strongly agree        6-Agree        5-Slightly agree        4-Neither agree nor disagree        3-Slightly disagree        2-Disagree        1-Strongly disagree                    In most ways my life is close to my ideal.            The conditions of my life are excellent.            I am satisfied with my life.            So far I have gotten the important things I want in life            If I could live my life over, I would change almost nothing.                        
Other questionnaires are available to measure pleasant and unpleasant affect. For example, PANAS (Positive and Negative Affect Scale) is designed to separately measure both positive and negative affect. Development and validation of a brief measure of positive and negative affect: The PANAS scales. Journal of Personality and Social Psychology, 54, 1063-1070. This scale tends to measure aroused or activated states of affect (e.g., excitement and distress), and thus it might be preferable in some situations to use scales that measure a wider range of emotions (e.g., contentment and embarrassment). In addition to the above measures, a description of useful measures can be found in the prior art.
The assumption behind self-reports of SWB is that the respondent is in a privileged position to report his or her experience of well-being. Indeed, only the respondent can experience her or his pleasures and pains. Thus, self-report measures are critical and particularly appropriate in the field of rehabilitative management systems.
Self-report scales that are designed to measure SWB usually correlate with each other, and converge with SWB assessed by other methods. However, because of the potential shortcomings of self-report measures (e.g., response biases, memory biases, and defensiveness), researchers have worked to develop other ways of measuring SWB and protect the integrity of the data. For example, people's frequency of smiling, their ability to recall positive versus negative events from their lives are useful measures of SWB. In addition to the standard questionnaires that are well-known in the art, alternative methods based on self-reports such as interviews and the experience sampling method (mood reports collected at random moments over a period of weeks) have also been utilized. In addition, behavioral observations of affect expression in natural settings correlate with informant reports of emotion. Finally, electrophysiological measures also converge with self-reports of SWB. It is encouraging that measures based on diverse methodologies correlate and provide similar estimates of well-being because the multi-measure approach helps rule out artifactual explanations of the self-report data.
As discussed above, SWB is primarily defined in terms of the internal experience of the respondent. In its truest form, an external frame of reference is not imposed when assessing SWB. However, external frames of reference may be valuable in normalizing or correlating SWB data to events influencing groups or populations of individuals.
For example, researchers have found that all demographic factors together accounted for less than 20% of the variance in SWB. Variables such as education, ethnic status, and age often correlate at very low levels with reports of SWB. In addition, income in the U.S.A. correlates only about 12% with SWB. Thus, it seems that demographic variables such as age, education, sex, ethnicity and wealth often have weak relations to SWB.
Nevertheless, some demographic variables do consistently predict SWB. For example, married people of both sexes report more happiness than those who are never married, divorced, or separated. See Lee, G. R., Seccombe, K., & Shehan, C. L. (1991). Marital status and personal happiness: An analysis of trend data. Journal of Marriage and the Family, 53, 839-844. One benefit of marriage may be providing interesting and supportive social interactions for the individual. Furthermore, there is evidence that happy people are more likely to marry in the first place, so the causal influence between SWB and marriage may work in both directions. See Mastekaasa, A. (1992). Marriage and psychological well-being: Some evidence on selection into marriage. Journal of Marriage and the Family, 54, 901-911; Scott, C. K. (1991). In addition to the effects of marriage on participants, there are differences in SWB between the children of intact marriages versus divorced marriages. Life satisfaction is lower when one's parents had a highly conflictual marriage or when they were divorced, and this pattern is true in both individualistic and collectivistic cultures.
Another important area in assessing SWB is the distinction between on-line measures of well-being (at the moment) versus global reports of longer periods that are based on memory. If people's experiences over time are sampled randomly, a measure of their on-line levels of SWB can be obtained. Often pagers, alarm watches, or hand-held computers are used for the random experience sampling method to assess whether most of a person's moments are pleasant or unpleasant.
In sum, SWB attempts to understand people's self-evaluations of their lives. These evaluations may be primarily cognitive (e.g., when a person gives conscious evaluative judgments about his or her satisfaction with life as a whole, or evaluative judgments about specific aspects of his or her life such as perception of health) or might consist of the frequency with which people experience pleasant emotions (e.g., joy) and unpleasant emotions (e.g., depression). Furthermore, SWB is fairly consistent under most demographic variables. Thus, by obtaining a baseline measurement of a person's SWB, the medical practitioner can utilize that information as a positive reinforcement mechanism or to correlate the persons' SWB to objective medical data. In this way, SWB can serve as a rehabilitative management tool and might also serve as a predictive health management and assessment tool.
For these and other reasons, there is a need to provide a primary input system to assess a person's physical and emotional SWB that allows both a person and/or a medical practitioner to easily and quickly access the information. The system also must be capable of storing and correlating the information so the person and medical practitioner can observe trends of SWB. Finally, the input system must be easy to use and encourage compliance and data input, yet robust enough to provide useful data to the practitioner and the person.